The present invention relates to a method for the improvement of a gramophone record. More particularly, the invention relates to a method by which electrostatic charge on the surface of a gramophone record is greatly reduced and the anti-wearing resistance of the gramophone record is remarkably enhanced resulting in decreased noise generation in the playing of the record even after many times of repeated playing.
As is well known, most of the gramophone records in modern times are manufactured with a copolymeric resin of vinyl chloride and vinyl acetate. Despite the many advantages obtained by the use of such a vinyl chloride-based resin, on the other hand, gramophone records made of the resin have several problems due to the relatively poor anti-wearing resistance and high susceptibility to electrostatic charging resulting in the early stain of the surface by the deposition and accumulation of dusts with consequent rapid growth of the noise generation in playing of the record.
Accordingly, it has been an urgent demand to develop an effective method for the improvement of the gramophone records of a vinyl chloride-based resin with respect to the above mentioned problems. For example, there have been proposed various chemical methods for the treatment of the record surface with an object to improve the surface strengths or, in particular, the anti-wearing resistance. Unfortunately, no satisfactory method has been yet developed not only by the reason of insufficient effectiveness of the method but also by the economical reason with increased costs to so large an extent.
In order to prevent electrostatic charging, i.e. accumulation of static electricity, on the surface of a gramophone record, there are known a method of coating the surface with an antistatic agent and a method of incorporating an antistatic agent into the resin composition by blending prior to fabrication of the resin composition into a gramophone record. The former method of coating is effective when instant exhibition of the antistatic effect is desired. The method of coating is, however, defective due to the poor durability of the antistatic effect and the stickiness of the coated surface eventually leading to blocking of the surface-coated gramophone records stacked one on another or kept standing side by side. The latter method of the impregnation of the resin composition with an antistatic agent is insufficient in the effectiveness of the antistatic performance even though more durable than the former method. Increasing of the amount of the antistatic agent in compensation for the insufficient antistatic effect may leads to the appearance of stickiness on the surface consequently with blocking or increased stain of the surface in addition to the disadvantages of poor heat resistance and inferior workability of the resin composition.